The World Health Organization defined probiotics as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.1 Many foods and supplements contain live microorganisms, but only characterized strains with a scientifically demonstrated effect on health may correctly be termed ‘probiotics’. By this definition, a probiotic strain must have the characteristics of specificity, potency, and demonstratable clinical efficacy.
Fermented foods such as kimchi and sauerkraut contain microbes and have been associated with health benefits but are not considered probiotics as they have not been characterized, the ‘adequate amount’ (or dose) has not been defined, and their health effects have not been clinically demonstrated.
Probiotics are identified through their genus, species, subspecies, and strain. The strain level is important as clinical results of probiotics are directly related to that specific strain.2 For example, the Chr. Hansen probiotic strain Lactobacillus rhamnosus, LGG® is primarily associated with gastrointestinal and immune function,3, 4, 5, 6 while the Lactobacillus rhamnosus, GR-1® strain is predominantly associated with women’s urogenital microflora.7, 8
Probiotic products contain millions to billions of live bacteria, each of which can form visible colonies that can be used for enumerating the bacteria; thus, the potency of a product is measured through Colony Forming Units. Probiotic potency at the ‘end of shelf life’, a product's potential expiration date, needs to be within the dosage range of documented clinical results that are specifically associated to that specific probiotic strain.9, 10 The number of viable bacteria will have decreased between manufacturing and purchasing, therefore, the potency at end of shelf life, rather than on the date of manufacture, should be reported on the product.
Composition of the human gastrointestinal microbiome fluctuates over a lifetime, with imbalances (dysbiosis) occurring due to age, medications, diet, and disease.11 Additionally, mode of delivery at birth and exposure to antibiotics affects the development of our gut microbiome.12 Some probiotics have been associated with specific effects across a range of diverse health areas, by positively influencing the dysbiotic microbiota.
Probiotics have been extensively studied in vitro, in vivo, and in human double-blind clinical trials for decades, and have demonstrated health benefits across different health areas. The suggested mode of action for probiotics involves supporting the integrity of the intestinal epithelial barrier,13, 14 maintaining healthy immune responses,15, 16 promotion of enteroendocrine cell hormone secretion17 and support for production of beneficial metabolites.18, 19 Examples of health areas where certain probiotic strains have been associated with a beneficial effect are listed below.
Gastrointestinal health is an example of a health area in which probiotic products have demonstrated a beneficial effect. Supplementation with probiotic products containing specific Chr. Hansen strains has been associated with increased defecation frequency in adult populations with infrequent bowel movements,20, 21, 22 and with the management of the symptoms of infant colic23 – an effect that is thought to occur through support for the healthy microbiota structure and function.23
In infants and children Chr. Hansen strains have been associated with support for a healthy immune function. Consumption of strain-specific probiotic products have been associated with reduced incidence of respiratory infections,24, 25 respiratory tract infections lasting > 3 days,5 a significantly lower number of days with respiratory symptoms,5 and reduced incidence of acute otitis media.25
Chr. Hansen probiotic strains have been associated with support for healthy urogenital microbiota, with observations of reduced incidence of urinary tract infections,7 vulvovaginal candidiasis,26 and bacterial vaginosis.8, 27, 28
Oral health is a fourth example of an area in which probiotic supplementation has demonstrated positive support. In children, consumption of products containing a Chr. Hansen probiotic strain has been associated with a decreased risk of dental caries based on a clinical evaluation and a microbiological analysis, and lower Streptococcus mutans levels from dental plaque and saliva.29, 30
When choosing a probiotic product, it is important to pay attention to the CFU count of the probiotic strain in the product and the potency of the probiotic strain that was investigated in the associated clinical trial.
For more information on our Chr. Hansen strains, click here.
LGG® and GR-1® are registered trademarks of Chr. Hansen A/S.
The article is provided for informational purposes regarding probiotics and is not meant to suggest that any substance referenced in the article is intended to diagnose, cure, mitigate, treat, or prevent any disease.
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2. McFarland LV, et al. Strain-Specificity and Disease-Specificity of Probiotic Efficacy: A Systematic Review and Meta-Analysis. Frontiers in medicine. 2018;5:124-. (PubMed)
3. de Vrese M, et al. Probiotic lactobacilli and bifidobacteria in a fermented milk product with added fruit preparation reduce antibiotic associated diarrhea and Helicobacter pylori activity. J Dairy Res. 2011;78(4):396-403. (PubMed)
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20. Eskesen D, et al. Effect of the probiotic strain Bifidobacterium animalis subsp. lactis, BB-12®, on defecation frequency in healthy subjects with low defecation frequency and abdominal discomfort: a randomised, double-blind, placebo-controlled, parallel-group trial. Br J Nutr. 2015;114(10):1638-46. (PubMed)
21. Uchida K, et al. Effect of fermented milk containing Bifidobacterium lactis BB-12 on stool frequency, defecation, fecal microbiota and safety of excessive ingestion in healthy female students. Journal of Nutritional Food. 2005;8:39-51
22. Pitkala KH, et al. Fermented cereal with specific bifidobacteria normalizes bowel movements in elderly nursing home residents. A randomized, controlled trial. J Nutr Health Aging. 2007;11(4):305-11. (PubMed)
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26. Martinez RC, et al. Improved treatment of vulvovaginal candidiasis with fluconazole plus probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14. Lett Appl Microbiol. 2009;48(3):269-74. (PubMed)
27. Vujic G, et al. Efficacy of orally applied probiotic capsules for bacterial vaginosis and other vaginal infections: a double-blind, randomized, placebo-controlled study. Eur J Obstet Gynecol Reprod Biol. 2013;168(1):75-9. (PubMed)
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29. Nase L, et al. Effect of long-term consumption of a probiotic bacterium, Lactobacillus rhamnosus GG, in milk on dental caries and caries risk in children. Caries Res. 2001;35(6):412-20. (PubMed)
30. Glavina D, et al. Effect of LGG yoghurt on Streptococcus mutans and Lactobacillus spp. salivary counts in children. Coll Antropol. 2012;36(1):129-32. (PubMed)